1. Field of the Invention
The present invention relates to a rotation angle detecting apparatus for detecting a rotation angle of a detected body using a magnetic resistor and a permanent magnet.
2. Description of the Related Art
Conventionally, known examples of rotation angle detecting apparatuses include those in which permanent magnets are mounted to an end portion of a rotating shaft, a magnetoresistive sensor is disposed so as to be axially aligned with the rotating shaft and so as to be separated from the permanent magnets and perpendicular to the rotating shaft, and a rotation angle of the rotating shaft is detected by the magnetoresistive sensor responding to magnetic flux originating from the permanent magnets in a direction perpendicular to the rotating shaft (See Patent Literature 1, for example).
Patent Literature 1
Japanese Patent Laid-Open No. HEI 11-94512 (Gazette)
In the above rotation angle detecting apparatus, one problem has been that much of the magnetic flux originating from the permanent magnets leaks outside a region to which the magnetoresistive sensor responds, requiring larger permanent magnets and increasing costs.